Explanation:
In the 1920s, pictures from the Hooker Telescope on Mt. Wilson fundamentally
changed our understanding of the cosmos. Astronomer
Edwin Hubble,
using photographs he took with this
telescope,
demonstrated that the objects his contemporaries
called "spiral nebulae" were actually huge systems of stars - spiral
galaxies, similar to our own Milky Way galaxy but incredibly distant.
Prior to Hubble's work
it was argued that
the spiral nebulae were mere clouds of gas and that they, along with
everything else in the universe, were contained in our own galaxy.
The Hooker Telescope mirror is 100 inches in diameter which is
nearly the size of the mirror
of the orbiting Hubble Space Telescope named in Hubble's honor.
The Mount Wilson Observatory offers a
"virtual walking tour"
of this historic telescope.